U.S. Pat. No. 6,402,799 discloses a cyclonic separator in which a gas-liquid mixture is injected via a tangential inlet into a horizontal vortex tube in which the gaseous and liquid fractions are at least partly separated and the liquid fraction forms a film alongside the inner wall of the vortex tube and is discharged via a radial outlet, whereas the gaseous fraction is concentrated near the central axis of the vortex tube and discharged via a central outlet.
International patent applications WO9901194 and WO03029739 disclose cyclonic separators wherein a gas stream is accelerated in a vortex tube to a near sonic or supersonic velocity and thereby expanded and adiabatically cooled such that liquid or solid particles are formed which are discharged via an outlet at the outer circumference of the tube, whereas a dry gas fraction is discharged via a central outlet. These known separators are configured to remove liquefied and/or solidified components from a gas stream and not to remove a gaseous fraction from a carrier liquid.
UK patent GB2035150; U.S. Pat. Nos. 2,811,219 and 4,596,586 and International patent application WO03055575 disclose cyclonic separators in which a gas-liquid mixture is injected via a tangential inlet into a vertical vortex tube which has at its upper end a central gas outlet conduit via which the gaseous fraction is discharged and at its lower end a liquid collecting basin which is connected to a liquid discharge conduit.
A disadvantage of the latter group of cyclonic separators is that they generally are large pieces of equipment and have a limited separation efficiency. German patent application DE 3715157 suggests a cyclonic separator for separating gaseous components from a liquid wherein the liquid is injected via a tangential inlet into a tubular gas-liquid separation chamber which comprises at one end a liquid outlet and at an opposite end a gas outlet. A disadvantage of this known separator is that the liquid is first induced to swirl at the entrance of the separation chamber and then accelerated in a converging annular throat section, which reduces the gas-liquid separation efficiency.
International patent application WO 03/002227 suggests a cyclonic liquid degassing separator in which a liquid stream is first induced to swirl by swirl imparting vanes arranged in an inlet conduit and the swirling liquid stream is then accelerated in a converging throat section in which substantially liquid and gaseous fractions are formed, whereupon the gaseous fraction is discharged through a central gas outlet conduit and the liquid fraction is discharged through an annular liquid outlet conduit. A disadvantage of this method is that the liquid stream is first induced to swirl and then accelerated in the converging throat section, which reduces the gas-liquid separation efficiency.